THE UNCERTAINTY PRINCIPLE
by Jess Brook
Summary: Sherlock is left conflicted after Empathy from Shadows and but Moriarty isn't one to deal with sharing. Sequal to Empathy from Shadows, M rated for sexual content later. John/Sherlock and Sherlock/Moriarty within, you have been warned!
1. Chapter 1

Precisely Measured

-John Hamish Watson

Mycroft had said it had to be tonight.

He'd called me to the Diogenes club again he said it was important, that he needed to know for his brother sake, for mine. "I need to know John, lives depend on you again I'm afraid." He'd raised that eyebrow of his, he knew the bloody buttons to push alright. He never did answer whose life would depend on me but I could only assume it was Sherlock's who else would be damaged by words he writes?

It felt wrong invading Sherlock's privacy like that, but he swore to me it was crucial to do this; that I had it in my power to save lives if I did this one thing that Sherlock himself wouldn't think twice about doing to me.

I waited until I knew he'd left the house. I crept into his room to find it, it was dark and dismal had always been but lain on the bed between ruffled sheets was what I needed. The leather bound journal looked ancient until you noticed the elastic strap used to close it and the fountain pen clipped onto that.

He would certainly know that I'd touched it, opened it invaded his privacy as I resented when he did it to me. He'd probably assume I'd planned it from the out, get him to write about how he feels just so I could keep track of it by reading it. My hands trembled at a little as I picked it up, pulling the elastic away revealing the first page, dated last week.

He talked about empathy, using spiteful words and venomous tones aiming them at me. Even reading it, it's like he predicted I would be here. The very last word on that page struck me like a dagger.

Hypocrite.

I couldn't deny it to myself, here I was reading his personal thoughts when it frustrated me as soon as he did it. I had to keep reading, even if it felt like kicking him in the teeth after word I read. Mycroft had said to look for something unusual, but every page after the first was less personal it looked like he'd started to use it as a notebook for his research.

Reading down the first page was the usual experience of reading Sherlock's notes which meant I was left with utterly no clue.

The Copenhagen Interpretation: A study into the uncertainty principle

"∆χ ∆p ≥" h/2

As the equation so acutely puts it, we can establish that knowing both the position and momentum of any given quantum particle at one moment is an impossibility. Much like the observer effect the mere act of measuring one of those quantities changes the other, thus if you were to measure where an electron was with any accuracy its velocity and momentum would change in the same instant.

This leaves us with the rather simplistic adage to describe the phenomenon:

The more precisely one quantity is measure, the less accuracy you have of in knowing the other quantity.

It went on like that, just words with little meaning to me. After a while I placed the diary back exactly how it was, very sure I'd missed some detail or other that would incriminate me later. I walked out of the room on slightly wobbling legs, I had to tell Mycroft what I'd read about regardless of its importance to me.

Picking up my phone on the way to my bedroom I dialled in Mycroft's personal number, the one he would actually answer first ring, and he did.

"John I assume you've done it." His voice full of deep British accent.

"Yes" I paused trying to compile my thoughts. "But there wasn't anything different just what looked like another research project of his."

"What was the topic?" He asked curiously, maybe even slightly amused.

"Something about" I could feel my eyebrows furrowing even over the phone "an uncertainty theory, I think it was something about physics but you know what his notes are like"

"Ah, my dear brother is improving with his codes I see. Thank you John, it's what I needed" he hung up.

Just like that, he'd made me betray the trust of his own brother and my own flat mate and hung up as if it were nothing more than a game he played every day.


	2. Chapter 2

The Holmes boy!

Mycroft had promised his diary, a place he might mock but every disguise is a self-portrait.

He hadn't so much as dropped a text and it was starting to get boring, time to play another game with the younger Holmes. Mycroft stepped into the case looking out of place dressed in what looked like a rather expensive suit but it would never outdo a Westwood. He smiled in a fake manner; taking a seat opposite still looking rather stuck up.

"James" he nodded, holding himself in that sickeningly regal manner.

"Croftie." I grinned, returning his mocking persona with little jabs. "Do you have it then?" I dropped the act with his lack of response, dull as usual but why had I expected better from Holmes honestly.

I sipped at my tea, watching him form a calculated response. "Physics" he said cocking his head slightly sideways "the uncertainly principle if we're being precise." His eyebrow quirked a little, as if asking if it meant anything.

I sat my tea down on the table with a splash. Physics that's how he wanted to describe that evening, with physics; practically insulting.

But oh he is good. ≥H/2… yet I'd taken the cherry off of the younger Holmes cake. Johnny boy would be jealous…

I collected myself, waving a green plastic file in front of his face. "I suppose you want this then?" my voice returned to the sarcastic lightness, bribing him with a little un-associated tip bits, it was almost too easy. His face, its usual empty boringness "It is part of our deal, James."

I slide it across the table, smirking. "I hope it makes for delightful reading." I took a final slow sip "I do have to dash though." His hands snapped the file up, pulling it under the desk quickly as I stood to leave.

"Text me, Croftie." I winked, leaving him shaking his head as I exited the door. The Holmes boys, weren't they fun. It really was a shame he was ever so taken with that detective inspector, he would have made such a brilliant game but I had a better one for tonight.

I walked up, getting into the spotless BMW outside. I settled myself across the back seats, legs slung across the seat before tapping the back of the driver's seat. "The apartment." I called quickly before grabbing my phone and texting Sebastian.

Get Sherlock, bring him home. –JM

I tapped the screen of my phone rhythmically; oh I would get rid of half of the equation if it took all night. I really wish it took all night.

He'll be in the flat by 6 Boss. –SM

I let myself relax, my shoulder dropped a fraction. I'd need all the energy I could save for tonight, whether he felt like playing along or not. If I was less controlled, I might have said I couldn't wait along longer as the car pulled up outside the lavish flat I shared with Sebastian.

I could wait, but I didn't particularly want to.

Hours I'd been pacing around the flat, hours. I'd wondered more than once why I paid Seb if he was so pitifully slow when I needed him.

The familiar tap, tap, tap of the stairs reverberated inside the flat. Gentle and singular so he was alone, and seemingly willing or at very least compliant or Sebastian is empty handed and he would regret that if he were.

The suspense, oh this was a good game. I heard the door sliding softly across the carpet followed by someone's own soft footsteps announcing his anticipated arrival.

"Jim, I didn't mean to be seeing you quite so soon" his voice caressed the air, somewhat sarcastically but overall not entirely irritated which was a good start.

"Oh well" I turned watching Sherlock head towards the chair opposite with an airy confidence. "You know me; I got bored, fancied a physics lesson." I smirked as his eyebrow quirked up.

"Physics?" he slumped into the chair. Oh he did have to persist in being obvious didn't he?

"Oh Sherly you didn't think your diary would be secret forever did you?" My smirk grew yet more pronounced this better take all night. "I did love the analogy though, bit flawed though." His face was a master piece, I wondered how long it took him to figure out it was John; I really wanted a photo of that.

"No I hadn't." He tapped his fingers on his knee "I didn't have you down for a physics man though."

"I didn't take you for a man's man." I grinned "But it seems we are both wrong" I crossed my legs, eyes examining his own body language.

"Also I can break your theory; I know where this evening is going as well as where it starts." I chuckled ruining his pretty little metaphor.

"So you can read minds too can you?" his voice cold, typically so because he was shutting down but that wasn't okay.

"You're hardly difficult to read dear" my eyes fluttered over his body, the fidgeting hands, the tense posture it really was obvious.

"I Have to tell you Sherlock dear, I don't 'do' sharing." I paused, here came the kicker. "Not with dear doctor Watson anyway."


End file.
